Nonmetal-Metal Strategy to Reduce Ru-O Covalency while Promoting Local Reactive Water Concentration for Efficient Acidic Oxygen Evolution.

Wang, Mingming; Li, Xinyi; Wang, Zhongfeng; Huang, Hong; Sun, Xiaoyuan; Chen, Hailong; Luo, Hao; Li, Lu et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

Affordable, active, and durable oxygen evolution reaction (OER) catalysts are crucial for proton exchange membrane water electrolysis (PEMWE). The low-cost RuO<sub>2</sub>, relative to IrO<sub>2</sub>, is attractive for acidic OER while suffering from durability. To resolve this activity-stability dilemma of RuO<sub>2</sub>, we propose a universal nonmetal-metal strategy to reduce Ru-O covalency while promoting local reactive water concentration for efficient acidic OER. The nonmetal-metal dual-dopant via complementary regulation of O 2<i>p</i> and Ru 4<i>d</i> bands weakens the Ru-O covalency, constraining the lattice oxygen participation and Ru dissolution. Operando evidence further unravels that the best-performing B-Cr-RuO<sub>2</sub>, via surface OH, increases the local reactive water concentration and the connectivity of H-bond networks, enabling an order of magnitude enhancement in intrinsic activity without sacrificing durability over RuO<sub>2</sub>. Consequently, the B-Cr-RuO<sub>2</sub>-incorporated PEMWE delivers attractive performance for practical applications, requiring a voltage of only 1.54 V@1.0 A cm<sup>-2</sup> and maintaining a durable operation at industrial current densities.